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Re: st: example about choice experiment datasheet


From   elisabetta capobianco <elisabetta.capobianco@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: example about choice experiment datasheet
Date   Tue, 27 Nov 2012 06:31:44 +0100

Dear Arne,
you're my very helpful, thank you so much.
Now i'm trying to use mix logit, I've ridden your article. It seems to
be better than asclogit, because i have different alternatives on N
choices occasion. Is it more correct for my case, isn't it?

Thank you!

elisabetta

2012/11/26 Arne Risa Hole <arnehole@gmail.com>:
> This is to be expected; if you found it surprising you need to read
> the -asclogit- manual entry more carefully. Whether it's correct or
> not really depends on what you are trying to do. I would suggest that
> including socio-demographics in your model only makes sense if you
> interact them with the alternative-specific attributes, since your
> alternatives are unlabelled.
>
> Arne
>
> On 26 November 2012 10:43, elisabetta capobianco
> <elisabetta.capobianco@gmail.com> wrote:
>> Ok Arne,
>> now It's clear and I have had good results.
>> Just a doubt. When I put inside the socio-demographic variables, the
>> output has the four alternatives 1,2,3,4, even if I write nocons.
>> I don't understand the meaning of this output considering that I have
>> unlabelled alternatives.
>> Is however correct this result?
>>
>> Thank you,
>> Elisabetta
>>
>>
>>
>>
>>
>> 2012/11/24 Arne Risa Hole <arnehole@gmail.com>:
>>> Elisabetta,
>>>
>>> The "case" variable must a unique identifier for each choice. You can
>>> generate it like this
>>>
>>> egen caseid = group(id scenario)
>>>
>>> The "alt" variable should be coded 1,2,3,4,1,2,3,4 etc. (not
>>> 1,2,3,4,5,6,7,8,...).
>>>
>>> Arne
>>>
>>> On 24 November 2012 16:04, elisabetta capobianco
>>> <elisabetta.capobianco@gmail.com> wrote:
>>>> Thank you Arne, I have taken the book.
>>>> My problem is that I have 16 scenarios for id (n=131) with 4 different
>>>> alternatives for each scenario .
>>>> So in the dataset I have written for each id non 4 alternatives
>>>> (1,2,3,4) but 64 alternatives. Is it correct?
>>>>
>>>>
>>>>
>>>> id   scenario      alt
>>>> 1         1            1
>>>> 1         1            2
>>>> 1         1             3
>>>> 1         1            4
>>>> 1         2            5(or1?)
>>>> 1         2            6(or2?)
>>>> 1         2            7(or3?)
>>>> 1         2            8 (or4?)
>>>> 1         3            9(or1?)
>>>> .
>>>> .
>>>> .
>>>> .
>>>> .
>>>> 1         16           64
>>>> 2         1              1
>>>> .
>>>> .
>>>> And when I wrote:
>>>> asclogit choice organic price, case(id) alternatives(car) noconst
>>>>
>>>> case is id or scenario? I suppose scenario. But if is scenario I don't
>>>> know how to use id!
>>>> And alternatives are the 64 alternatives?
>>>>
>>>>
>>>> Thank you so much for your help.
>>>>
>>>> elisabetta
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> 2012/11/23 Arne Risa Hole <arnehole@gmail.com>:
>>>>> Elisabetta
>>>>>
>>>>> I am fairly sure that you can use -asclogit- to do what you want. If
>>>>> you don't want alternative-specific constants you can use the
>>>>> -noconst- option. Modifying the example in the help-file slightly:
>>>>>
>>>>> webuse choice
>>>>> asclogit choice dealer, case(id) alternatives(car) noconst
>>>>>
>>>>> As you can see the only coefficient which is estimated in this case is
>>>>> the one for the dealer attribute, which is analogous to the organic
>>>>> and price attributes in your experiment. In your case the variable
>>>>> that identifies the alternatives for each case ("car" in the example)
>>>>> can simply take the values 1, 2, 3 and 4 since your alternatives are
>>>>> unlabelled.
>>>>>
>>>>> I also recommend taking a look at a basic choice modelling text before
>>>>> proceeding, such as
>>>>> http://books.google.co.uk/books/about/Applied_Choice_Analysis.html?id=8yZrtCCABAgC.
>>>>>
>>>>> Good luck!
>>>>>
>>>>> Arne
>>>>>
>>>>> On 23 November 2012 13:25, elisabetta capobianco
>>>>> <elisabetta.capobianco@gmail.com> wrote:
>>>>>> I think that asclogit is not the right comand for me.
>>>>>> Because I have 4 unlabeled alternatives, 16 diferrent scenarios with 4
>>>>>> alternatives for 131 individuals. So my indipendent viariables are the
>>>>>> attributes and dipendent variables the utility for each level of
>>>>>> attribute.
>>>>>> I need to know the importance of every level, not of alternatives.
>>>>>> Ex.:n=131
>>>>>> scenario 1)   A       B        C         D
>>>>>>      organic  org   no org   no org   org
>>>>>>      price       4         8         4         4
>>>>>> scenario 2)   A      B         C        D
>>>>>>     organic  no org  no org   org     no org
>>>>>>       price     12     16         8        8
>>>>>> .
>>>>>> .
>>>>>> .
>>>>>> Perhaps with mixlogit? Because the example is on a specific
>>>>>> alternative, car or bus.
>>>>>> I instead need to know the coefficient of attributes and levels.
>>>>>>
>>>>>> I don't know if I have explained well, I hope!
>>>>>>
>>>>>> e
>>>>>>
>>>>>>
>>>>>>
>>>>>> 2012/11/23 Arne Risa Hole <arnehole@gmail.com>:
>>>>>>> -help asclogit_postestimation-
>>>>>>>
>>>>>>> Arne
>>>>>>>
>>>>>>> On 23 November 2012 11:05, elisabetta capobianco
>>>>>>> <elisabetta.capobianco@gmail.com> wrote:
>>>>>>>> Dear Arne,
>>>>>>>> i need to estimate the marginal effect of levels on attributes of my choice.
>>>>>>>> Is it possible?
>>>>>>>> es:
>>>>>>>> about meat:
>>>>>>>> attribute   level
>>>>>>>> label        organic/not organic
>>>>>>>> origin       local abroad
>>>>>>>> prize        4/8
>>>>>>>>
>>>>>>>> I would know the utility for each level of each attribute.
>>>>>>>>
>>>>>>>> Thank you!
>>>>>>>> elisabetta
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> 2012/11/21 elisabetta capobianco <elisabetta.capobianco@gmail.com>:
>>>>>>>>> Thank you so much Arne!!!
>>>>>>>>> I'm creating the data set and then i'll try to run in Stata!
>>>>>>>>>
>>>>>>>>> Elisabetta
>>>>>>>>>
>>>>>>>>> 2012/11/20 Arne Risa Hole <arnehole@gmail.com>:
>>>>>>>>>> Elisabetta
>>>>>>>>>>
>>>>>>>>>> -mlogit- is not very useful to model data from choice experiments as
>>>>>>>>>> it does not allow alternative-specific explanatory variables.
>>>>>>>>>> -asclogit- requires your data to be in long form (one row per
>>>>>>>>>> alternative); see -help asclogit- and the first example in the paper I
>>>>>>>>>> mentioned in my last email.
>>>>>>>>>>
>>>>>>>>>> Arne
>>>>>>>>>>
>>>>>>>>>> On 20 November 2012 10:04, elisabetta capobianco
>>>>>>>>>> <elisabetta.capobianco@gmail.com> wrote:
>>>>>>>>>>> Thank you Arne, I want to use asclogit and mlogit for my choice modelling.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> 2012/11/19 Arne Risa Hole <arnehole@gmail.com>:
>>>>>>>>>>>> Elisabetta
>>>>>>>>>>>>
>>>>>>>>>>>> As Jay says the correct data form depends on the estimation command
>>>>>>>>>>>> you are planning to use, so this is a very important piece of
>>>>>>>>>>>> information that you haven't given us. You may find the examples in
>>>>>>>>>>>> http://www.stata-journal.com/article.html?article=st0133 useful.
>>>>>>>>>>>> Generally speaking the best strategy is to import the data into Stata
>>>>>>>>>>>> and then use commands like -reshape- to convert the data into the form
>>>>>>>>>>>> you want, rather than trying to do this in Excel.
>>>>>>>>>>>>
>>>>>>>>>>>> Arne
>>>>>>>>>>>>
>>>>>>>>>>>>> On 19 November 2012 15:51, elisabetta capobianco
>>>>>>>>>>>>> <elisabetta.capobianco@gmail.com> wrote:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Thank you for your answer!
>>>>>>>>>>>>>> I want to do a mixed logit, but I have found a data set on help file
>>>>>>>>>>>>>> with just one choice set. I have 16 choice sets and I don't know how
>>>>>>>>>>>>>> to fil the excel data set.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> 2012/11/18 JVerkuilen (Gmail) <jvverkuilen@gmail.com>:
>>>>>>>>>>>>>> > On Sun, Nov 18, 2012 at 4:11 AM, elisabetta capobianco
>>>>>>>>>>>>>> > <elisabetta.capobianco@gmail.com> wrote:
>>>>>>>>>>>>>> >> Hi, I'm new of statalist and stata!
>>>>>>>>>>>>>> >> I'm working on choice experiment about food preferences in schools.
>>>>>>>>>>>>>> >> I have 4 alternatives unlabelled, 4 attributes and 4 levels, 130
>>>>>>>>>>>>>> >> individuals.
>>>>>>>>>>>>>> >> I have the data base in excel, but before insheet the file in stata
>>>>>>>>>>>>>> >> i'm not sure that i have put the data in the right mode in the excel
>>>>>>>>>>>>>> >> file.
>>>>>>>>>>>>>> >> Have you got an example on a excel datasheet about choice modelling?
>>>>>>>>>>>>>> >> Just an example to understand how to organize my datasheet.
>>>>>>>>>>>>>> >
>>>>>>>>>>>>>> > It depends on what analysis you want to use. -clogit- and procedures
>>>>>>>>>>>>>> > like it that are using alternative-specific predictors use the same
>>>>>>>>>>>>>> > basic format, which is specified in the help file. You can see the
>>>>>>>>>>>>>> > example dataset there. Essentially it is a "long" format like
>>>>>>>>>>>>>> > person-period in a growth model with time-varying covariates.
>>>>>>>>>>>>>> > *
>>>>>>>>>>>>>> > *   For searches and help try:
>>>>>>>>>>>>>> > *   http://www.stata.com/help.cgi?search
>>>>>>>>>>>>>> > *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>>>>>> > *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> --
>>>>>>>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>>>>>>>>>> eventuali documenti allegati
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>>>>>>>>>> destinatario. Nel caso
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>>>>>>>>>> che la sua diffusione
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>>>>>>>>>> prontamente avviso
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> *
>>>>>>>>>>>>>> *   For searches and help try:
>>>>>>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> *
>>>>>>>>>>>> *   For searches and help try:
>>>>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> --
>>>>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>>>>>>> eventuali documenti allegati
>>>>>>>>>>>
>>>>>>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>>>>>>> destinatario. Nel caso
>>>>>>>>>>>
>>>>>>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>>>>>>> che la sua diffusione
>>>>>>>>>>>
>>>>>>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>>>>>>> prontamente avviso
>>>>>>>>>>>
>>>>>>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>>>>>>
>>>>>>>>>>> *
>>>>>>>>>>> *   For searches and help try:
>>>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>>
>>>>>>>>>> *
>>>>>>>>>> *   For searches and help try:
>>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>>>>> eventuali documenti allegati
>>>>>>>>>
>>>>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>>>>> destinatario. Nel caso
>>>>>>>>>
>>>>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>>>>> che la sua diffusione
>>>>>>>>>
>>>>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>>>>> prontamente avviso
>>>>>>>>>
>>>>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>>>> eventuali documenti allegati
>>>>>>>>
>>>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>>>> destinatario. Nel caso
>>>>>>>>
>>>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>>>> che la sua diffusione
>>>>>>>>
>>>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>>>> prontamente avviso
>>>>>>>>
>>>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>>>
>>>>>>>> *
>>>>>>>> *   For searches and help try:
>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>
>>>>>>> *
>>>>>>> *   For searches and help try:
>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>
>>>>>>
>>>>>>
>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>> eventuali documenti allegati
>>>>>>
>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>> destinatario. Nel caso
>>>>>>
>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>> che la sua diffusione
>>>>>>
>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>> prontamente avviso
>>>>>>
>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>
>>>>>> *
>>>>>> *   For searches and help try:
>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>
>>>>> *
>>>>> *   For searches and help try:
>>>>> *   http://www.stata.com/help.cgi?search
>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>
>>>>
>>>>
>>>> --
>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>
>>>>
>>>>
>>>>           Le informazioni contenute in questa comunicazione e gli
>>>> eventuali documenti allegati
>>>>
>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>> destinatario. Nel caso
>>>>
>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>> che la sua diffusione
>>>>
>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>> prontamente avviso
>>>>
>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>
>>>> *
>>>> *   For searches and help try:
>>>> *   http://www.stata.com/help.cgi?search
>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>
>>> *
>>> *   For searches and help try:
>>> *   http://www.stata.com/help.cgi?search
>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>> *   http://www.ats.ucla.edu/stat/stata/
>>
>>
>>
>> --
>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>
>>
>>
>>           Le informazioni contenute in questa comunicazione e gli
>> eventuali documenti allegati
>>
>>           hanno carattere confidenziale e sono a uso esclusivo del
>> destinatario. Nel caso
>>
>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>> che la sua diffusione
>>
>>           e riproduzione è contraria alla legge e prego di darmi
>> prontamente avviso
>>
>>           e di cancellare quanto ricevuto. Grazie.
>>
>> *
>> *   For searches and help try:
>> *   http://www.stata.com/help.cgi?search
>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>> *   http://www.ats.ucla.edu/stat/stata/
>
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/faqs/resources/statalist-faq/
> *   http://www.ats.ucla.edu/stat/stata/



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          Le informazioni contenute in questa comunicazione e gli
eventuali documenti allegati

          hanno carattere confidenziale e sono a uso esclusivo del
destinatario. Nel caso

          questa comunicazione Vi sia pervenuta per errore, Vi informo
che la sua diffusione

          e riproduzione è contraria alla legge e prego di darmi
prontamente avviso

          e di cancellare quanto ricevuto. Grazie.

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/


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